<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>Document</title>
	</head>
	<body>
		<script type="text/javascript">
			function getTimestamp (done) {
				setTimeout(function() {
					
					// 执行调用者制定的事情
					done(Date.now())
				},1000)
			}
			// ===================================
			
			// 制定拿到数据过后怎么做
			var done = function (timestamp) {
				console.log(timestamp / 1000 / 60 / 60)
			}
			getTimestamp(done)
		</script>
	</body>
</html>
